• 한국결정성장학회지
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• 제29권5호
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• pp.229-237
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• 2019

야간이나 악천후에서도 높은 도로의 차선인식률을 유지하기 위해, 통상 재귀반사(retro-reflectivity) 특성이 뛰어난 고 굴절률의 글라스비드(glass bead)를 도로표시 페인트 위에 도포한다. 국가별로 일반 도로표시의 재귀반사 기준이 다르며, 국내는 백색광 기준으로 $240mcd/m^2{\cdot}lux$, 선진국들은 $250{\sim}300mcd/m^2{\cdot}lux$로 규정되어있다. 본 논문에서는 도로표시 관련 규정과 글라스비드에 대한 동향에 대하여 고찰하고, 향후 자율주행차량 상용화에 대비하여 규정 기준치 및 글라스비드물성 향상 필요성에 대하여 논의하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권1호
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• pp.211-224
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• 2019

This paper deals with a nonlinear controller based on saturation functions with variable parameters for set-point regulation and trajectory tracking control of an Autonomous Underwater Vehicle (AUV). In many cases, saturation functions with constant parameters are used to limit the input signals generated by a classical PD (Proportional-Derivative) controller to avoid damaging the actuators; however this abrupt bounded harms the performance of the controller. We, therefore, propose to replace the conventional saturation function, with constant parameters, by a saturation function with variable parameters to limit the signals of a PD controller, which is the base of the nonlinear PD with gravitational/buoyancy compensation and the nonlinear PD + controllers that we propose in this paper. Consequently, the mathematical model is obtained, considering the featuring operation of the underwater vehicle LIRMIA 2, to do the stability analysis of the closed-loop system with the proposed nonlinear controllers using the Lyapunov arguments. The experimental results show the performance of an AUV (LIRMIA 2) for the depth control problems in the case of set-point regulation and trajectory tracking control.

• Corrosion Science and Technology
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• 제21권6호
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• pp.514-524
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• 2022

Carbon emissions from fuel consumption have been pointed by scientists as the cause of global warming. In particular, fossil fuels are known to emit more carbon when burned than other types of fuels. In this regard, International Maritime Organization has announced a regulation plan to reduce carbon dioxide emissions. Therefore, recently, Liquefied Natural Gas propulsion ships are responding to such carbon reduction regulation. However, from a long-term perspective, it is necessary to use carbon-free fuels such as hydrogen and ammonia. Nitrogen oxides might be generated during ammonia combustion. There is a possibility that incompletely burned ammonia is discharged. Therefore, rather than being used as a direct fuel, Ammonia is only used to reduce NO_X such as urea solution in diesel vehicle Selective Catalyst Reduction. Currently, LPG vehicle fuel feed system studies have evaluated the durability of combustion injectors and fuel tanks in ammonia environment. However, few studies have been conducted to apply ammonia as a ship fuel. Therefore, this study aims to evaluate corrosion damage that might occur when ammonia is used as a propulsion fuel on ships.

• Geomechanics and Engineering
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• 제32권6호
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• pp.601-613
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• 2023

Low liquid limit silt, widely distributed in the middle and down reaches of Yellow River, has the disadvantages of poor grading, less clay content and poor colloidal activity. It is very easy to cause vehicle jumping at the bridge-embankment transition section when the low liquid limit silt used as the backfill at the abutment back. In this paper, a series of laboratory tests were carried out to study the physical and mechanical properties of the low liquid limit silt used as back filling. Ground granulated blast furnace slag (GGBFS) was excited by active MgO and hydrated lime to solidify silt as abutment backfill. The optimum ratio of firming agent and the compaction and mechanical properties of reinforced soil were revealed through compaction test and unconfined compressive strength (UCS) test. Scanning electron microscope (SEM) test was used to study the pore characteristics and hydration products of reinforced soil. 6% hydrated lime and alkali activated slag were used to solidify silt and fill the model of subgrade respectively. The pavement settlement regulation and soil internal stress-strain regulation of subgrade with different materials under uniformly distributed load were studied by model experiment. The effect of alkali activated slag curing agent on curing silt was verified. The research results can provide technical support for highway construction in silt area of the Yellow River alluvial plain.

• 청정기술
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• 제24권2호
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• pp.135-145
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• 2018

전 세계적으로 온실가스 배출량 저감을 위한 다양한 활동을 하고 있다. 국가별로는 UN에 개별 국가별 계획을 제출하기로 합의했으며, 기후변화와 관련한 제도를 운영하고 있다. 또한 기업들은 자체적으로 온실가스 배출량 산정 방법론 개발을 하고 있다. 본 연구에서는 환경영향 감축 효과를 산정하기 위한 방법론의 사전 연구를 수행하였고, 국제적, 국가별, 기업별로 구분하였다. 환경영향 감축 효과는 자동차 언더커버 제품과 유니소재화 제품에 적용하여 비교, 분석하였다. 제품 환경 발자국 감축 평가 방법에 따라 차이가 크게 나타났으며, 주요 원인으로는 시스템 경계의 차이, 데이터 수집 범위, 기존제품 대체량 설정 기준의 차이이다. 방법론별 결과값에 차이가 발생하기 때문에 이해관계자는 제품 환경발자국 감축 결과에 신뢰하지 못하고 있다. 이에 이해관계자가 쉽게 이해할 수 있는 수준의 제품 환경발자국 산정 방법론을 상세히 공개하도록 해야 한다. 장기적으로는 제품 발자국 평가방법의 표준화로 감축 결과에 대한 비교가 가능하게 할 필요가 있다.

• 한국자동차공학회논문집
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• 제19권6호
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• pp.68-75
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• 2011

A vehicle fuel economy is very important issue in view of fuel cost and environmental regulation. It has been improved according to the performance improvement of the vehicle engine, power train and many components. It was evaluated at given mode (LA-4, FTP-75, etc) on an engine dynamometer or computer simulation program. In this paper, the fuel economy improvement cruise control algorithms as controling a vehicle velocity by road load calculated and predicted in a real expressway with gradient was studied. Firstly, the altitude and distance data which was measured with GPS sensor was already installed in the ECU of a vehicle. Then the vehicle equipped with GPS receiver is driven the same expressway. The ECU calculates the gradient angle and the in-/decreasing velocity using the gradient angle by comparing the current received distance and altitude data from GPS with the saved data ahead of the vehicle. Therefore the ECU can calculate and predict the vehicle velocity considering tolerance velocity of next position with running. Then the ECU controls the vehicle velocity to meet this predicted velocity in all section. Three cruise control algorithms with the different velocity profiles for the improvement of fuel economy are proposed and compared with the computer simulation results that the vehicle runs on Youngdong expressway. The proposed CVELCONT2 and CVELCONT3 algorithms were improved 3.7% and 4.8% of fuel economy compared with CONSTVEL which is steady cruising algorithm. These two algorithms are recommended as the Eco-cruise drive methodologies in this paper.

• 한국전산구조공학회논문집
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• 제28권2호
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• pp.169-176
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• 2015

교량의 교각 설계시에는 설계기준에 의거하여 차량의 충돌에 대비한 적절한 방호시설 등이 고려되고 있으나, 지하차도의 기둥 설계시에는 차량의 충돌과 관련된 규정이 없다. 또한 지하차도의 기둥은 상대적으로 폭이나 두께가 작아서 차량의 충돌에 의하여 큰 손상이 발생할 수 있다. 본 논문에서는 지하차도 기둥에 대한 충돌해석을 통하여 차량의 충돌에 의한 구조물의 손상을 평가하였다. 충돌해석에서는 지하차도 기둥의 물성과 형태 그리고 차량의 속도와 종류 등이 매개변수로 고려되었다. 수치해석 결과 지하차도 기둥이 심하게 손상되는 경우가 있었으며 따라서 지하차도의 기둥 설계시에는 차량 충돌에 대한 적절한 고려가 필요하다.

• 한국항공운항학회지
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• 제13권3호
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• pp.43-60
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• 2005

In september 2004, a new pilot certificate scheme referred to as Sport Pilot Certificate was declared official and standardized in the US. The designation of Light-sport aircraft and the details of the relevant pilot certificate policy was announced out of the perception that a new regulation is required to be applied whereby the limitations on the manufacturing process enhancements and current aviation rules are considered the triggering factors. US Federal Aviation Regulation retains a comprehensive range of airworthiness certificates and aircrafts are managed systematically in accordance with FAR 21, 103. The airworthiness are further segregated into sub categories, which allows differentiated management. Korean Aviation Law classify aircraft into five different categories and powered air vehicle that weighs more than 150kg(19liters fuel capacity) for one seat, 225kg for two seats(38liters fuel capacity) while the systems that fall under a specific mass threshold level are known as ultralight vehicle. The research discusses the policy of the sport pilot certificate and the light-sport aircraft ratings announced official by the Federal Aviation Administration in an intuitive fashion with the analysis of the operations providing the evidence as to the viability of adopting the policy in local grounds. Based on the findings, the report discusses the case for introducing the light-sport aircraft and make recommendation on a strategy of applying the policy in Korea with respect to the pilot certificates, safety agenda, and the written test for the pilot certificate, and operating efficiency.

• 한국IT서비스학회지
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• 제15권4호
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• pp.25-39
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• 2016

The drone is an unmanned aerial vehicle which has no human pilot. Drones can be classified into military drones, commercial drones, and personal drones by usage. Also, drones can be classified from large-sized to nano-sized drone by size and autonomous, remote controlled drone by control type. Especially, military drones can be classified into low-altitude drones, medium-altitude, and high-altitude drones by altitude. Recently, the drone industry is one of the fast growing industries in the world. As drone technologies have become more advanced and cost-effective, Korean government has set its goal to become a top-level country in drone business. However, the government's strict regulation for drone operations is one of the biggest hurdles for the development of the related technologies in Korea and other countries. For example, critical problems for drone delivery can be classified into technical issues and institutional issues. Technical issues include durability, conditional awareness, grasp and release mechanisms, collision avoidance systems, drone operating system. Institutional issues include pilot and operator licensing, privacy rules, noise guidelines, security rules, education for drone police. This study analyzes the trends of the drone industry from the viewpoint of technology and regulation. Also, we define the business areas of drone utilization. Especially, the drone business types or models for public sector are proposed. Drone services or functions promoting public interests need to be aligned with the business reference model of Korean government. To define ten types of drone uses for public sector, we combine the business types of government with the future uses of drones that are proposed by futurists and business analysts. Future uses of drones can be divided into three sectors or services. First, drone services for public or military sectors include early warning systems, emergency services, news reporting, police drones, library drones, healthcare drones, travel drones. Second, drone services for commercial or industrial services include parcel delivery drones, gaming drones, sporting drones, farming and agriculture drones, ranching drones, robotic arm drones. Third, drone services for household sector include smart home drones.

• 한국분무공학회지
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• 제23권3호
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• pp.128-135
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• 2018

In this study, the following conclusions could be obtained from the analysis of emissions contribution rates and features for contaminated emissions by 13,456 gasoline vehicles passed in the vehicle load test (ASM-idle) under the inspection year 2013 to 2017. It was confirmed that the contamination of the CO, HC, NOx by the displacement is reduced on over 3L engine. As a result of comparing the exhaust gas in the low speed idle mode and the AS2525 mode, the exhaust gas in the low speed idle mode was measured high. It is estimated that if ISG function is applied, emissions from idle condition will be reduced. NOx emissions were reduced when the engine power was above 200HP. It has been confirmed that the amount of exhaust emissions are significantly reduced for vehicles manufactured after 2004. As a result of analyzing the exhaust gas according to the season, it is judged that there is a correlation between HC and NOx according to the ambient temperature. The concentration of exhaust emission in vehicles with high accumulated distance increases, which is considered to be the result of aging of the vehicle.